U.S. Pat. No. 4,443,477 discloses sulphonamidophenylcarboxylic acid compounds which inhibit thrombocyte aggregation. U.S. Pat. No. 4,258,058 discloses phenoxyalkyl carboxylic acid derivatives which are thromboxane A.sub.2 blocking agents. European Pat. No. 194,548A discloses sulphonamido-ethyl compounds which are useful in treating or preventing thrombembolic diseases by inhibiting thrombocyte aggregation.